Herz Guildford Heat Interface Unit

The Modern Solution for Apartment Heating and Domestic Hot Water Services

www.herzvalves.com

1

General Description

The Herz Guildford HIU is suitable for all community schemes and enables LTHW from a central plant to

provide heating and DHWS to each dwelling with complete hydraulic separation between the LTHW primary

and secondary heating and DHWS systems.

The HIU is a complete package comprising of all components mounted on a frame, factory assembled and

tested.

Main Components

Pressure Temperature Control Valve

As a hot water tap is opened the pressure temperature control valve reacts to the difference in pressure via a diaphragm and opens allowing the cold and primary heating water to flow through the heat exchanger. At the same time, a hot water priority valve closes the primary feed to the secondary heat exchanger, thus ensuring maximum flow is available at the domestic heat exchanger. In order to prolong the life of the DHW heat exchanger and prevent lime scale build up, the temperature of the domestic hot water is controlled by a thermostat fitted to the pressure temperature control valve. Using an immersion sensor, this thermostat controls the temperature of the hot water that exits the heat exchanger and regulates the pressure temperature control valve thus maximising the energy efficiency of both the HIU and the primary system. Summer Bypass Valve

The ”Summer bypass” valve utilises a return temperature limiter head fitted to a

thermostatic valve installed in a bypass between the primary flow and return

pipework within the HIU. This maintains a minimum primary temperature when

the space heating is not in use. The thermostatic bypass valve is installed

upstream of the heat meter. Combined with the Pressure Temperature Control

Valve, which only allows water through the DHW heat exchanger when there is

a demand, ensures that it is impossible to have meter creepage or standing

losses from the Herz Guildford HIU.

Primary Return Temperature Limiter

A return temperature limiter valve is installed in the primary return to

guarantee low primary return temperatures and maximise system efficiency.

In the Guildford UFH unit the return temperature limiter is replaced by a

thermostatic head with a contact sensor attached to the secondary flow pipe

to control the secondary temperature.

Hot water priority valve

Diaphragm

Mains cold water

Primary LTHW

Thermostatic insert

Double O ring system break

2

First Fix Rail

The First Fix Rail is a pre-assembled unit fitted with all the isolation ball valves required for the various circuits installed within the HIU. The unit is installed at first fix and allows shell and core pipework to be completed without the HIU being fitted. The first fix rail ball valves are fitted with drain valves to facilitate draining with integral test points fitted on the primary and secondary heating circuits to aid additional temperature or pressure measurement if required. The first fix rail with ball valves also allows maintenance to be carried out on the HIU as the main unit can be removed easily.

Top Entry stand-off Bracket

Other Features

Instantaneous hot water and space heating to properties

Twin heat exchangers provide hydraulic separation

Thermostatic hot water temperature control

Tempering valve to prevent risk of scalding

Differential Pressure Control Valve

Insulated back board, secondary heating heat exchanger & heating pipework

Insulated lockable cover with viewing window allows meter reading without casing removal

Low primary return temperature maximises system efficiency

Optional primary flushing bypass available

Option for heat meter (110mm Spool piece provided as standard)

Option for water meter (110mm Spool piece provided as standard)

Full WRAS approval

18mm stainless steel pipe work

Accessories available

Flushing bypass valve

WRAS Approved filling loop

Programmable room thermostat

Solenoid valve

Water meter

Presettable TRVs

For info on more accessories please

contact the Herz sales office

The Guildford HIU has the option to have a stand-off bracket

installed to enable the services to be connected from the top of the

unit. The top entry stand-off bracket enables any combination of

services to be piped from above or below the HIU. Pre-formed, pre-

insulated pipes, complete with all connections, are available to

provide full flexibility.

3

Functions

a) Residents Heating System

The primary flow to the heating system heat exchanger is controlled by a two port on/off actuated valve

linked to a programmable room thermostat (Herz 1 7795 01). This valve will close when the room

temperature setting has been achieved or when the heating system is not in use. A fixed spring differential

pressure control valve is fitted across the primary flow and return circuits on each HIU to protect the control

valves from excessive DP.

The secondary heating circuit is provided with an expansion vessel and secondary domestic heating pump which varies the system flow rate automatically based on demand.

b) Residents Hot Water (DHW)

Domestic hot water is generated via the DHW heat exchanger mounted in the HIU and provides instantaneous hot water on demand.

DHW temperature and primary flow rate through the heat exchanger is controlled via the Pressure temperature control valve, which is temperature compensated and requires no auxiliary power to operate.

When a hot water tap is opened the drop in pressure in the hot water pipe will open the 4 port pressure temperature control valve which in turn will allow primary hot water into the heat exchanger.

When the hot water demand ceases the pressure temperature control valve will immediately stop the primary flow into the heat exchanger. Therefore there is no drain on the primary heating when there is no demand, so no “extra energy usage” when residents are on holiday for example.

A tempering valve is provided to counter the effect of temperature overshoot caused when a hot tap is closed and opened again in a short space of time, this also ensures a stable output temperature.

A thermostatic “summer” bypass valve is fitted to maintain a minimum primary temperature when the space heating is not in use. This provides a quick DHW response and avoids unnecessary energy usage.

Energy Metering

As an option the HIU can be provided with a built in battery powered energy meter mounted in the primary heating return pipe.

The meter will measure flow using the ultrasonic principle with an accuracy complying with EN1434 and MID in Class 2 with dynamic range of 1:250 (qi:qp)

The heat meter has options for pulse, M bus or radio to allow remote reading with hand held scanner, drive by or remotely via GPRS. All necessary system hardware and software is available on request.

Pre-payment options are available on request.

If a cold water meter is fitted this can be pulse linked to the energy meter.

The heat calculator will display energy usage in kW hours.

Battery life approximately 12 years.

System Balancing

BSRIA BG 62/2015 states that each HIU should include a differential

pressure control device so that the operation of the HIU is

independent of fluctuations in the primary pressure. A Differential

Pressure Control Valve is included in the Herz Guildford HIU to

protect the HIU from pressure fluctuations in the primary system

and to govern the primary flow rate to the HIU. This means that the

Herz Guildford HIU is effectively self-balancing and requires no

other commissioning valves.

4

Technical Data

Guildford HIU Schematic

Guildford HIU UFH Schematic

No Description No Description

1 First fix pre-mounting rail ball valves 14 Space heating heat exchanger - Stainless Steel brazed

2 Summer bypass valve 15 Pressure relief safety valve

3 Return temperature limiter 16 Secondary circulating pump

4 Strainer 0.5mm mesh 17 Room temperature controller (optional)

5 Pressure gauge 18 Ultrasonic Heat meter with pockets (optional)

6 Expansion vessel 7.5 litres 19 Spacing piece (110mm) for water meter

7 Air vent 20 Differential pressure control valve

8 Tempering valve 21 Non-return valve

9 Zone valve 22 Thermostatic valve

10 Actuating drive for zone valve 23 Drain valve with test point

11 Pressure temperature control valve with hot water priority valve

24 Drain valve

12 Thermostatic head with contact sensor 25 Secondary flow temperature limiter (UFH version)

13 DHW heat exchanger - Stainless Steel brazed 26 Temperature safety switch (UFH version)

Primary F&R DHW Secondary F&R MWS

Primary F&R DHW Secondary F&R MWS

26

2

2

5

Guildford HIU Data

Guildford HIU Flow Data

Guildford HIU Part Numbers

Description Data

Maximum DHW output 55 kW (20 l/min) 73 kW (26 l/min)

Maximum secondary heating output 15 kW (8kW UFH)

Maximum primary supply temperature 90°C

Maximum DHW temperature 55°C

Maximum DHW flowrate 20 l/min & 26 l/min

Minimum DP at 85°C 25 kPa

Maximum working pressure primary side 10 bar

Maximum working pressure DHW side 10 bar

Minimum cold water pressure for maximum output 2.5 bar

Safety relief valve setting secondary heating side 3 bar

Safety relief valve stainless steel tail 18mm

Expansion vessel capacity 7.5 litres

Ball valve connections 22mm/15mm compression

Dimensions H x W x D 829mm (1010mm c/w ball valves) x 606mm x 190mm

Dimensions H x W x D (top entry) 829mm (1010mm c/w ball valves) x 674mm x 253mm

DHW 50/10°C 50/10°C 50/10°C 50/10°C DHW Temperature

Output Flowrate 70°C 75°C 80°C 85°C Primary Flow Temperature

33 kW 12 l/min 19 18 14.5 14.2 Primary Return Temp (°C)

554 506 437 406 Primary Flowrate (l/h)

42 kW 15 l/min 20.6 17.8 15.3 15 Primary Return Temp (°C)

721 627 547 513 Primary Flowrate (l/h)

55 kW 20 l/min 18 18.4 15.9 15.7 Primary Return Temp (°C)

880 832 731 689 Primary Flowrate (l/h)

73 kW 26 l/min 16.4 17.7 17.5 16.9 Primary Return Temp (°C)

1022 999 946 877 Primary Flowrate (l/h)

Heating capacity examples - Radiator Heating

Output Primary Flowrate Primary Temperature (°C) Secondary Temperature (°C)

5 kW 160 l/h 85/60 75/40

10 kW 320 l/h 85/60 75/35

15 kW 437 l/h 85/55 66/35

Heating capacity examples - Underfloor Heating

Output Primary Flowrate Primary Temperature (°C) Secondary Temperature (°C)

3 kW 79 l/h 75/41 45/40

5 kW 127 l/h 75/41 45/40

8 kW 193 l/h 75/39 45/35

Description Part no Part no inc.

bottom entry cover

Part no inc. top entry

cover

Herz Guildford HIU 20 l/min DHW 1401885 1402352 1402372

Herz Guildford HIU inc. Heat Meter 20 l/min DHW 1401889 1402353 1402373

Herz Guildford HIU 26 l/min DHW 1402321 1402358 1402378

Herz Guildford HIU inc. Heat Meter 26 l/min DHW 1402322 1402359 1402379

Herz Guildford UFH HIU 20 l/min DHW 1402213 1402356 1402376

Herz Guildford UFH HIU inc. Heat Meter 20 l/min DHW 1402214 1402357 1402377

Herz Guildford UFH HIU 26 l/min DHW 1402323 1402360 1402380

Herz Guildford UFH HIU inc. Heat Meter 26 l/min DHW 1402324 1402361 1402381

Herz Guildford HIU Cover 1401893

Herz Guildford HIU Cover for Top Entry 1401895

Herz Guildford First Fix Pre-Mounting Rail 1401896

Herz Guildford Top Entry Bracket 1401890

Herz Guildford Top Entry Bracket + Pipes 1401891

Herz Guildford Top Entry Pipe 1401894

6

Guildford HIU Accessories

Water Quality Consideration should be given to the use of a scale prevention device when aggressive water supplies are present. WRAS Approval Number Guildford HIU WRAS certificate No: 1412327 Guildford HIU Drawings

Bottom entry version Top entry version

HVHIUFL-01 WRAS approved filling loop for charging a secondary sealed system via temporary connection to the mains supply

Top entry pipe 1401887

First fix entry 1401888

Flushing bypass can be connected to the primary flow & return ball valves on the first fix pre-mounting rail or the pipes in the top entry bracket

1664002 Temporary flushing bypass can be connected onto the first fix pre-mounting rail before the HIU is fitted

1779501 Digital thermostat with individual time and temperature adjustment on a weekly basis with 9 fixed programs and 4 user programs, battery operated

HVHIUSV-01 Solenoid Valve for pre-payment applications supplied separately ½” NC 230V/50hz DIN plug included

HVHIUWM-01 SMART C+ single jet water meter WRAS approved, MID approved, can be installed in the Guildford HIU and fitted with a radio or pulse emitter

All specifications and statements within this brochure are according to information available at the time of printing and meant for informational purpose only. Herz Armaturen reserves the right to modify and change products as well as its technical specifications and/or it functioning according to technological progress and requirements. It is understood that all images of Herz products are symbolic representations and therefore may visually differ from the actual product. Colours may differ due to printing technology used. In case of any further questions don’t hesitate to contact HERZ.

7

Herz Valves UK Ltd. Progress House, Moorfield Point

Moorfield Road, Slyfield Industrial Estate

Guildford, Surrey GU1 1RU

Tel: 01483 502211, Fax: 01483 502025 E-Mail: sales@herzvalves.com

Herz Armaturen Gmbh

Richard-Strauss-Str. 22, A - 1230 Vienna Tel.: +43 (0)1 616 26 31-0, Fax: +43 (0)1616 26 31-27

E-Mail: office@herz.eu

www.herzvalves.com

www.herzvalves.com